The crash occurred around 3:13 a.m. on Aug. 19. A Tesla employee was driving the Semi eastbound on I-80 from Livermore, California, to a Tesla facility in Sparks, Nevada. The Semi approached a curve to the right and drove off the road before it crashed into a tree, continued down a slope, and rested against multiple trees, the agency said. The driver was not hurt.
Firefighters said previously that the battery reached 1,000 degrees Fahrenheit (540 degrees Celsius) while in flames.
The report stated that firefighters took precautionary measures and used an aircraft to spread fire retardant to cover the immediate area to stop the flames from spreading to a nearby forest.
After putting out the flames, authorities closed both directions of I-80 for around 15 hours so firefighters could ensure the batteries were at a safe temperature to begin the truck’s recovery. The vehicle was then monitored for 24 hours in an open-air facility. The agency reported that the battery did not reignite while under observation.
The agency found two main safety concerns through the investigation. The first was that vehicle manufacturers had poor emergency response guides. The second was gaps in the safety standards and research related to high-voltage lithium-ion batteries involved in high-speed, high-severity crashes, according to the report.
The agency suggested manufacturers reduce thermal runaway—uncontrolled increases in temperature and pressure—which can lead to battery reignition; safely store an electric vehicle with a damaged battery; provide vehicle-specific guidelines and information to first responders and other crash scene workers on the fire risks related to electric vehicles; and minimize the risks related to stranded energy in high-voltage lithium-ion batteries during and before a damaged electric vehicle is removed from the scene.
The investigation regarding the Tesla Semi crash in California is still ongoing to determine all aspects of the crash, according to the NTSB.
